Related Party Transactions (Details Textual) (USD $)	3 Months Ended		6 Months Ended			6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Jan. 15, 2008 Del Monte Center [Member]	Jun. 30, 2012 ICW Plaza [Member]	Jun. 30, 2011 ICW Plaza [Member]	Jun. 30, 2011 Valencia Corporate Center [Member]	Jun. 30, 2012 Reimbursements [Member]	Jun. 30, 2011 Reimbursements [Member]
Related Party Transactions (Textual) [Abstract]
Unsecured loans					$ 12,000,000
Debt instrument, maturity date			Mar. 01, 2013
Percentage interest on notes payable to affiliates					10.00%
Total rental income	54,964,000	48,616,000	109,284,000	93,582,000		1,100,000	1,200,000	900,000
Investment in WBW CHP LLC, in percentage			47.70%
Recovered reimbursements of operating expenses of WBW CHP LLC									$ 500,000	$ 400,000